Medical device anchor and method of manufacture thereof

ABSTRACT

A medical device anchor for use with electrical stimulation leads or catheters, and method of manufacture thereof. The anchor may include a gripping structure and a body portion molded on the gripping structure. The gripping structure forms a serpentine arrangement of a continuous nature with axial segments alternately interconnected between shoulder segments and bridging segments. The shoulder segments extend radially outward relative to the through hole further than the axial segments. The body portion may be formed by molding to securely capture the shoulder in the body portion, with the body portion being molded of material that is softer and more compliant than the gripping structure.

RELATED APPLICATION

This application claims priority to provisional U.S. Application Ser.No. 60/659,350, filed Mar. 7, 2005, the entire contents of which areincorporated herein by reference.

FIELD

This application relates to implantable medical leads and catheters,particularly to anchoring devices for use therewith.

BACKGROUND

Medical electrical leads or drug delivery catheters (hereafter referredto as therapy devices) are placed in the contact with biological tissueto delivery a therapy to the patient. These therapy devices are part ofa system that may include signal or implantable pulse generators (IPGs)or drug delivery pumps or combinations of such. The stimulators or pumpsin the system may be external to, or implanted in, the patient.

Medical electrical leads may be used, for example, to deliveryelectrical energy to various biological tissues such as the heart,brain, or peripheral nervous system, etc. For example, implantableleads, such as the Medtronic Model 3487A lead, have been used forstimulating the dorsal columns of the spinal cord, or implantable leads,such as the Medtronic Model 3587A, have been used for peripheral nervestimulation.

Medical drug delivery catheters, for example, may be used to deliverytherapeutic agents to the intrathecal space of the spinal canal, or tothe blood vasculature, or brain ventricles, etc. Catheters such as theMedtronic Model 8703 may be used for these types of applications.

Retention devices, typically referred to as anchors, are utilized tosecure these leads and catheters thereby prevent lead or cathetermovement or migrations. U.S. Pat. No. 5,843,146, which is assigned toMedtronic, discloses a medical lead anchor for anchoring a medical leadrelative to, for example, the epidural space of the spinal cord.

Another such anchor is the Medtronic Model 3550 EZ Anchor. This anchorconsisted of a molded elastomer, e.g., medical grade silicone rubber,suitable for long-term implantation into a patient. The surface of theModel 3550 EZ Anchor is covered with a pattern of bumps. The bumps allowsutures to be placed in a constricting manner around the midportion ofthe anchor.

Yet another example is U.S. Pat. No. 4,553,961 (Pohndorf et al), whichis entitled “suture sleeve with structure for enhancing pacing leadgripping.” One of the embodiments of the suture sleeve of the Pohndorfet al '961 patent includes a gripping enhancing structure, whichcomprises a framework of an undulating or sinuous, continuous ribincluding axially extending segments, or simply axial segments, andshort partially circular segments, or simply short circular segments.Each short circular segment connects an adjacent pair of axial segmentsat one end of the framework. Each axial segment of the sinuous rib isspaced an equal distance from each of the adjacent axial segments andthis formation purportedly allows for compressibility of frameworkagainst a lead body. The short circular segments of the Pohndorf et al'961 patent are shown as being at the same radial distance or positionrelative to the through-bore of the suture sleeve.

BRIEF SUMMARY OF EXEMPLARY EMBODIMENTS

As used herein, the term, “exemplary” is used in the sense of “forexample” or “for purposes of illustration,” and not in a limiting sense.

An exemplary medical device anchor is adapted to prevent or resisttherapy device migration after the implantation of leads or catheters ina patient. Implantable neurostimulation systems are exemplified in thisapplication for purposes of illustration, but one skilled in the artwould realize that the concepts presented would be applicable to othermedical devices such as heart pacemaker and defibrillators as well asdrug delivery devices and methods.

Exemplary embodiments of the medical device anchor provide: 1) securelead or catheter retention by compression of beams or linked beams, 2)positive fixation of the gripping element or structure within a softbody of the medical device anchor, 3) unrestricted suture locationwithin a suture zone of the anchor body, 4) soft, flexible tipsminimizing or reducing tissue interactions.

A first exemplary embodiment is a medical device anchor that generallycomprises a gripping structure and a body portion. The grippingstructure has a generally tubular configuration defining axial andradial directions. The gripping structure being defined or formed by anannular shoulder and a plurality of compressible beams extending axiallyfrom the annular shoulder wherein the shoulder extends radiallyoutwardly beyond the beams. The body portion is formed by molding aroundthe gripping structure and retains the shoulder within the body portion.The gripping means and body portion define a lumen extending in theaxial direction for receiving a lead or catheter.

A second exemplary embodiment is a medical device anchor that generallycomprises a gripping structure and a body portion. The grippingstructure forms or defines a through hole having a circumference,wherein axial, circumferential and radial directions are definedrelative to the through hole. The gripping structure is formed by aplurality of compressible axial segments, a plurality of shouldersegments and a plurality of bridging segments. The plurality ofcompressible axial segments are arranged in a generally parallel, spacedapart array along the circumference of the through hole, with each axialsegment having first and second ends. The plurality of shoulder segmentsarea separated from one another in alternating fashion by a plurality ofshoulder gaps forming a generally annular array of shoulder segments andshoulder gaps, with the first ends of the axial segments beingalternately bridged or unbridged by the shoulder segments and shouldergaps. The shoulder segments extend radially outward relative to thethrough hole further than the axial segments. The plurality of bridgingsegments are separated from one another in alternating fashion by aplurality of unbridged gaps forming a generally annular array ofbridging portions and unbridged gaps, with the second ends of the axialsegments being alternately bridged or unbridged by the bridging segmentsand unbridged gaps such that the gripping structure forms a serpentinearrangement of a continuous nature with the axial segments alternatelyinterconnected between shoulder segments and bridging segments. The bodyportion is formed by molding to retain the shoulders within the bodyportion, the gripping structure and body portion defining a lumen forreceiving a lead or catheter.

A third exemplary embodiment is a suture sleeve assembly comprising asuture sleeve made of soft elastomeric material and means associatedwith the suture sleeve for enhancing gripping of a lead body by thesuture sleeve. The suture sleeve comprises a tubular sleeve having athroughbore adapted to receive a lead body or catheter. The grippingenhancing means is made of a material that is different than thematerial of the suture sleeve and which is stiff but flexible, and thegripping enhancing means is positioned to extend within andlongitudinally of an elongate axis of the suture sleeve in asuture-receiving area of the suture sleeve intended to receive one ormore sutures thereby to disperse any stress placed upon said suturesleeve when sutures are tied along the suture-receiving area. The suturesleeve assembly is radially compressible upon the placement and tying ofa suture around the suture sleeve assembly in the suture-receiving areato facilitate generally uniform gripping of the lead body or catheter bythe suture sleeve assembly along the length of the gripping enhancingmeans. The gripping enhancing means comprises a cylindrical flexibleframework within a suture sleeve forming a cylindrical envelope. Theframework is defined by an undulating or sinuous arrangement of acontinuous rib extending in axial segments connected by arcuate segmentswherein the arcuate segments define two shoulders extending radiallyoutwardly relative to the through bore farther than the axial segments,and the two shoulders define the suture-receiving area.

A fourth exemplary embodiment is a method of manufacturing the medicaldevice anchor generally comprising forming a gripping structure of thetype described above in which the shoulder segments extend radiallyoutward relative to the through hole farther than the axial segments,and molding a body portion on the gripping structure to securely capturethe shoulder in the body portion, the body portion being molded ofmaterial that is softer and more compliant than the gripping structure.

A fifth exemplary embodiment is a method of manufacturing the medicaldevice anchor generally comprising forming a gripping structure of thetype described above in which the shoulder segments extend radiallyoutward relative to the through hole farther than the axial segments,and stretching a body portion on the gripping structure with theshoulder segments securely captured by the body portion, the bodyportion being molded of material that is softer and more compliant thanthe gripping structure.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates an exemplary embodiment of a neurostimulationenvironment.

FIG. 2 illustrates an exemplary embodiment of a stimulation system.

FIG. 3 illustrates an exemplary embodiment of the electrical stimulationlead also shown in FIGS. 1 and 2.

FIG. 4 shows an exemplary embodiment of a drug delivery environment.

FIG. 5 shows an exemplary embodiment of a drug delivery system.

FIG. 6 shows the exemplary embodiment of a catheter of FIGS. 4 and 5.

FIG. 7 is a perspective view of preferred exemplary embodiment of amedical device anchor.

FIG. 8 is an exploded view of the medical device anchor of FIG. 7.

FIG. 9 is a perspective view of an exemplary embodiment of a grippingstructure of the medical device anchor of FIGS. 7 and 8.

FIG. 10 is a right side view of the gripping structure of FIG. 9.

FIG. 11 is a top view of the gripping structure of FIGS. 9 and 10.

FIG. 12 is a cross-sectional view of the gripping structure of FIGS.9-11.

FIG. 13 is an exploded view of an alternate exemplary embodiment of themedical device anchor.

FIG. 14 is a cross-sectional view of the medical device anchor of FIG.13.

FIG. 15 is a perspective view of an exemplary embodiment of a grippingstructure of the medical device anchor of FIGS. 13 and 14.

FIG. 16 is a cross-sectional view of the gripping structure of FIG. 15.

FIG. 17 is a second perspective view of the gripping structure of FIGS.15 and 16 rotated relative to the view of FIG. 15.

FIG. 18 is a perspective view of the medical device anchor illustratingan exemplary application of sutures.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 1 shows a general environmental view 10 for an exemplaryimplantable neurostimulation system embodiment. Neurostimulation systemsmay be used to treat conditions such as pain, movement disorders, pelvicfloor disorders, gastroparesis, and a wide variety of other medicalconditions. As illustrated in FIGS. 1 and 2, the neurostimulation system20 may include a neurostimulator 22, one or more stimulation leadextension(s) 30, and one or more stimulation lead(s) 40. Theneurostimulator 22 is typically implanted subcutaneously in thepatient's body 28 at a location selected by the clinician. Thestimulation lead 40 is typically fixed in place near the locationselected by the clinician using a device such as an adjustable anchor.An exemplary location is within the epidural space for electricalstimulation of the spinal cord, or in or along the brain, or in muscleor subcutaneous tissue.

The exemplary implantable neurostimulator 22 has a housing, a powersupply in the housing 24, and stimulation electronics in the housing inelectrical communication with the battery and in electricalcommunication with a connector block 26, which may also be known as aterminal block.

The exemplary stimulation lead 40, shown in FIG. 3, has a proximal endportion 45, a distal end portion 41 and a lead body 43 extending betweenthe proximal end portion 45 and distal end portion 41. The proximal endportion 45 has at least one electrical connector 46 (also known aselectrical terminals or contacts), with various standard pluralities,such as four or eight electrical contacts, being typical. The distal endportion 41 has at least one stimulation electrode 42, with variousstandard pluralities, such as four or eight electrodes, being typical.The exemplary stimulation lead 40 is of the type sometimes referred toas a percutaneous lead, where the lead may have a generally cylindricalconfiguration throughout its length to facilitate less invasive,percutaneous implantation techniques for totally implanting the lead.Suitable alternatives include surgical or paddle style leads in which anenlarged paddle section is provided on the lead, and the electrodes aretypically arranged along the paddle section.

There is at least one lead conductor 49 contained in the lead body 43that is electrically connecting the electrical connector 46 to thestimulation electrode 42. Typically, at least one conductor may be usedto establish electrical communication between a single electricalconnector/electrode pair, although alternative examples includemultiplexing or bus features within the lead to allow use of fewerconductors along the length of the lead than the number of electrodes.As used herein, “conductive means” or “means for electricalcommunication between electrodes and electrical connectors include theforegoing examples or any alternative structure to allow selection orelectrical activation of one or more electrode.

FIG. 4 shows a general environmental view 50 for an exemplary embodimentof an implantable drug delivery system 52. Drug delivery systems may beused to treat conditions such as pain, movement disorders, diabetes anda wide variety of other medical conditions. As illustrated in FIGS. 4and 5, the drug delivery system 52 may include a drug delivery pump 54,and a catheter having a proximal catheter portion 56 and a distalcatheter portion 58. The drug pump 54 is typically implantedsubcutaneously in the patient's body 60 at a location selected by theclinician. The distal catheter portion 58 is typically fixed in placenear the location selected by the clinician using a device such as anadjustable anchor.

The exemplary implantable drug delivery pump 54 may have a housing 62,and a power supply, pumping mechanism and pump electronics in thehousing 62. The pumping mechanism may be in direct communication withthe catheter through a connector 64 on the housing 62.

The catheter is typically has a tubular configuration with a lumenextending longitudinally throughout the catheter. Implantable cathetersmay be formed of various medical grade materials, including for examplesilicone or polyurethane. More that one lumen may alternatively bepresent in the catheter. The therapy delivery element in a drug deliverysystem may include a distal catheter and an optional proximal catheter.Elements may be included in proximal catheter to provide hoop strengthto the device to prevent kinking or crushing of the proximal catheter.

FIGS. 7-11 illustrate an exemplary embodiment of a medical device anchoror suture sleeve 70 having a body portion 72 and gripping element orstructure 74, both shown in an exploded view in FIG. 8. The grippingelement or structure 74 constitutes an exemplary embodiment of a meansassociated with the suture sleeve for enhancing gripping of a lead bodyor catheter by the suture sleeve, or gripping enhancing means.

The gripping structure 74 may be formed of a material having differentmechanical properties than the material of the body portion 72. Thegripping structure 74 may, for example, be formed of relatively stiffmaterial in comparison with the material of the body portion 72. Thebody portion 72 may be formed, for example, of soft, resilientlycompressible material, such as elastomeric or substantially elastomericmedical grade material (e.g., silicone or polyurethane), includingwithout limitation silicone rubber having a Shore A hardness ofapproximately 45-55. The gripping structure 74 may be formed, forexample, of Titanium or Titanium alloy material.

As illustrated in FIG. 9, the gripping structure 74 may includecompressible axial segments or beams 76 separated by slots (e.g., slots78 and 80), and raised shoulders 82 and 84 at opposite ends of the axialsegments 76, with the axial segments and raised shoulders defining agenerally cylindrical lumen or through hole 86. Axial, circumferentialand radial directions are defined relative to the through hole 86.

In the exemplary embodiments shown in FIGS. 7-11, four axial segments 76and four shoulder segments 90, 92, 94 and 96 are illustrated, but itwill be understood that alternative numbers of such axial segments andshoulder segments may be provided.

The gripping structure 74 may be viewed as a generally cylindricaltubular structure being partially split by a first slot 78 and secondslot 80 extending longitudinally from opposite ends 98 and 99 of thegripping section 74, where the first and second slots 78 and 80 definetwo planes approximately perpendicular to one another. The first slot 78bisects the cross-section of the gripping structure 74 along a firstplane from the first end 98 of the gripping structure 74 up to shoulder82 (shoulder segments 90 and 92). The second slot 80 bisects thecross-section of the gripping structure 74 along a second plane from thesecond end 99 up to shoulder 84 (shoulder segments 94 and 96). The firstand second planes defined, respectively, by the first and second slots78 and 80 are approximately perpendicular to one another. Slot 78 formtwo gaps one along each of first and second opposite sides of thegripping structure, and slot 80 forms two gaps one along each of thirdand fourth opposite sides of the gripping structure. Slots 78 and 80 (orthe gaps formed thereby) allow the gripping section to be compressed bythe application of a radial force, such as suture. The grippingstructure 74 thus forms a serpentine arrangement of a continuous naturewith the axial segments 76 (defined between the slots) alternatelyinterconnected between shoulder segments 90, 92, 94 and 96. As usedherein, the terms “plane” or “planes” (e.g., “first plane” or “secondplane”) are used in a geometric sense to establish relative positions ororientations and such planes do not constitute physical structure butmerely are used to define an illustrative relationship between elements,such as the axial segments or first and second slots, that do constituteillustrative or exemplary physical structure.

It will be appreciated that the gripping structure may alternativelyinclude a different number of slots extending from opposite ends in asimilar fashion to first and second slots 78 and 80. For example, fourslots (not shown) could be provided in which two slots extend inwardlyfrom each end, the slots extending from the same end define planes thatare approximately perpendicular to each other, and the slots extendingfrom opposite ends define planes that are offset by approximately 45degrees from one another.

The plurality of the compressible axial segments 76 may be, for example,arranged in a generally parallel, spaced apart array along thecircumference of the through hole 86, with each axial segment havingfirst and second ends. The plurality of shoulder segments 90 and 92 or94 and 96 of each of shoulders 82 and 84 are separated from one anotherin alternating fashion by a plurality of shoulder gaps forming, for eachshoulder, a generally annular array of shoulder segments and shouldergaps. The first ends of the axial segments are alternately bridged orunbridged by the shoulder segments 90, 92 and shoulder gaps of firstshoulder 82, and the second ends of the axial segments are alternativelybridged or unbridged by the shoulder segments 94, 96 of the secondshoulder 84 such that the gripping structure forms a serpentinearrangement of a continuous nature with the axial segments alternatelyinterconnected between shoulder segments 90, 92, 94 and 96.

The shoulder segments 90, 92, 94 and 96 extend radially outward relativeto the through hole farther than the axial segments. The axial segmentarray may be viewed as defining a first infinite cylinder surroundingand tangent with the axial segment array, with the at least one of theshoulder segments (but preferably all of the shoulder segments 90, 92,94 and 96) being substantially entirely radially outward of the firstinfinite cylinder. As used herein, the term “infinite cylinder” refersto a geometric concept of a cylinder having an infinite length whosecircumferential surface is defined by the axial segment array tofacilitate understanding the geometric arrangement or relationship ofthe shoulders or shoulder segments relative to the axial segment array.The term “infinite cylinder” is not an actual physical structure of suchgripping structure.

Most preferably, each of the shoulder segments 90 and 92 include aportion extending axially beyond the first ends of the axial segments,and each of the shoulder segments 94 and 96 include a portion extendingaxially beyond the second ends of the axial segments. This arrangementis best shown in FIG. 15 with respect to a single shoulder having twoshoulder segments in the context of a different embodiment of themedical device anchor. The body portion may then be molded tosubstantially surround such extended portions of the shoulder orshoulders for particularly effective retention of the gripping structurewithin the body portion. The extended portions of the shoulders may beviewed as being positioned radially outside the first infinite cylinder.

In a preferred example, threads 88 or other suitable texture is providedon the inner surface of the axial segments 76 (and optionally in theshoulders) for retention against a catheter or lead held within thelumen 86. FIG. 11 is a cross-sectional view of gripping structure 74illustrating an exemplary embodiment of the inner surface of the lumen86 of gripping structure 86. The inner surface may be intentionallyroughened to increase the frictional force to resist lead or catheterwithdrawal when a tensile force is applied to the lead or catheter. Thisroughened surface may take a multitude of forms, with a preferredexemplary form being that of threads 88. Threads 88 are shown in FIG. 11to completely cover the lumen-defining surfaces, although thelumen-defining surfaces of the axial segments 76 could be roughened,with the inner surfaces of the shoulder segments in at least one examplebeing separated from the lumen by material of the body portion.

Exemplary surface features, such as bumps 90, may be provided along theouter surface of the midportion of the body portion 72, and tapered endportions 92 and 94 may also be provided.

FIGS. 13-17 illustrate an alternate exemplary embodiment of a medicaldevice anchor 100 including a body portion 102, gripping means orgripping structure 104 and sleeve 106. Sleeve 106 substantiallyenclosing the outer surface of the gripping structure 104 to provide ashield during an exemplary insert molding process. Sleeve portion 106may be tubing fabricated from a material such as polytetrafluorethylene,nylon or other materials, but is preferably formed of the same orsimilar material to that used to mold the body portion (e.g., siliconerubber).

The body portion 102 includes a midportion 108 and tapered endportions110 and 112. The body portion 102 has a lumen or through hole 114therethrough defining a longitudinal direction, with the lumen orthrough hole 114 being adapted to accept a lead or catheter. Bodyportion 102 is made from biocompatible materials such as siliconerubber, polyurethane or other elastomer.

Midportion 108 has an outer surface on which a pattern of bumps areformed. The illustrative bumps are spheroidal in nature, but couldassume other geometric shapes. In practice, a suture or sutures may beplace circumferentially around the midportion 108 to apply aconstricting force effecting lead or catheter retention. Optionally, thebody portion 102 may alternatively or additionally include radialgrooves in the outer surface providing suture locations.

Gripping means 104 and sleeve 106 are shown in situ in the body portion102 in FIG. 14. The gripping means 104 and sleeve 106 may be positionedsuch that the tapered endportions 110 and 112 are symmetrically locatedabout the gripping means 104.

FIGS. 15-17 illustrate various features of the exemplary gripping means104. The gripping means 104 may include two zones, a shoulder zone (thezone defined by shoulder 116) and a beam zone (between 118 and 120).Beam zone 118-120 has an outer diameter of appropriate size to fitwithin the inner diameter of sleeve portion 106, preferably with amodicum of friction. Shoulder zone 116 and beam zone 118-120 define alumen or passageway therethrough for accepting a stimulation lead orcatheter (which is the same as lumen 114 when the gripping means 104 andbody portion 102 are assembled (e.g., the body portion is overmoldedonto the gripping means).

Shoulder zone 116 functions to provide an anchor point for the grippingmeans 104 within the body portion 102. This mechanical fixation withinthe body portion 102 facilitates the gripping means staying securely inplace to avoid sliding in a longitudinal direction within body portion102.

In addition to the shoulder 116, the gripping structure 104 may have aplurality of compressible axial segments 122 and a plurality of bridgingsegments 124. The axial segments 122 may be arranged in a generallyparallel, spaced apart array along the circumference of the through hole114, with each axial segment having first and second ends.

The shoulder 116 may include a plurality of shoulder segments 126separated from one another in alternating fashion by a plurality ofshoulder gaps 128 forming a generally annular array of shoulder segments126 and shoulder gaps 128. The first ends of the axial segments 122 maybe alternately bridged or unbridged by the shoulder segments 126 andshoulder gaps 128, with the shoulder segments 126 extending radiallyoutward relative to the through hole 114 farther than the axial segments122. The plurality of bridging segments 124 may be separated from oneanother in alternating fashion by a plurality of unbridged gaps 130forming a generally annular array of bridging segments 124 and unbridgedgaps 130, with the second ends of the axial segments 122 beingalternately bridged or unbridged by the bridging segments 124 andunbridged gaps 130 such that the gripping structure 104 forms aserpentine arrangement of a continuous nature with the axial segments122 alternately interconnected between shoulder segments 126 andbridging segments 124.

As discussed above with respect to the exemplary embodiment of FIGS.7-12, the axial segment array may be viewed as defining a first infinitecylinder surrounding and tangent with the axial segment array, with theat least one of the shoulder segments (but preferably all of theshoulder segments 126) being substantially entirely radially outward ofthe first infinite cylinder. In addition, the axial segments 122 mayalso be viewed as defining a second infinite cylinder tangent with theaxial segment array and sandwiching the axial segment array between thesecond infinite cylinder and the first infinite cylinder, with thebridging segments 124 being substantially enclosed between the first andsecond infinite cylinders.

In an alternative embodiment (not shown in the drawings), the bridgingportion 124 could be omitted leaving the axial segments unconnected atthe distal or second ends thereof.

The gripping structures 74 and 104 are illustrated as having a generallytubular configuration defining a passageway or lumen for receiving alead or catheter. As used herein, “tubular” includes hollow cylindricalor other hollow structures, such as hollow structures having elliptical,polygonal or irregular cross sections, so long as a passageway or lumenis formed therein. As used herein, “circumference” is used broadly toinclude the equivalent property with respect to tubular structures asdefined above.

The shoulders may function as a stabilizing mechanism for the grippingmeans. Once the gripping means is embedded within the body portion, theshoulder may provide a mechanical interference preventing thelongitudinal movement of the gripping means relative to the bodyportion.

FIG. 16 is a cross-sectional view of an exemplary gripping means 104showing the inner surface of axial segments 122. The inner surfaces ofthe axial segments may have features for increasing the fictional andmechanical gripping strength of the axial segments 122 against the leador catheter. For example, a thread like surface 123 may be provided.This could also be other formed in a knurled or geometric bumpconfiguration.

The gripping means 104 may be fabricated from a variety of materialssuch as engineering thermoplastics or metals. These may include, forexample, thermoplastics such as polyurethane, polysulfone, polycarbonateor similar materials and metals such as titanium, stainless steel orother alloys suitable for implantation in the body.

FIG. 18 shows an exemplary application of the sutures. In use, sutures200 may be placed around the midportion 108 of the anchor 100 andtightened sufficiently to cause a constricting force that deflects thegripping section's midportion 108. This deflection causes the axialsegments 122 inner surface to engage the outer surface of the lead orcatheter effecting the fixation desired. Two sutures are shown forpurposes of illustration, although a single suture or more sutures maybe used.

It will be appreciated that the feature of the sleeve 106 of theexemplary embodiment of FIGS. 13-18 may be combined with the doubleshoulder embodiment illustrated in FIGS. 7-12. In this case the, sleeve(not shown) may have generally tubular shape with a length appropriateto allowing the shoulders to mate opposite ends of the sleeve. Theeffect of this matching may be to capture the gripping structurepreventing it from being easily dislodged from sleeve.

The medical device anchor may be fabricated by a number of procedures.In an exemplary transfer molding process, a mold defining ½ of the outersurface of body portion 102 is filled with an elastomer such as siliconerubber. A force plate is used to provide a cavity where the grippingmeans 104 with sleeve portion 90 mated to it will be placed. Two suchhalves are filled. The force plates are removed and the gripping meanswith sleeve are inserted into one of the mold halves along with amandrel to form lumen. The other half is assembled and the mold is thenprocessed with heat and pressure to vulcanize the material. If sleeveportion 106 is omitted, elastomer may be forced into the recesses andvoids of gripping means 104, possibly preventing proper actuation andloss of retention force.

In an exemplary insertion or injection molding procedure, the grippingmeans 104 and sleeve 106 are placed on a mandrel that forms the lumenand placed in a mold defining the outer surface of body portion 102.Under pressure, the material to be used for the body portion 102 isforced into the mold. The mandrel and sleeve 106 prevent the materialfrom penetrating the gaps between the axial segments while allowing theshoulder or shoulders to be embedded in the material of the body portion102.

In an exemplary assembly process, the sleeve and gripping structure maybe fabricated separately and then assembled. If employed, the optionalsleeve, being a soft, elastomeric material, can be stretched or dilatedto allow the gripping structure to be inserted into it. The body portionmay be stretched over or on the gripping structure with the shouldersegments securely captured by the body portion, with the body portionbeing molded or otherwise formed of material that is softer and morecompliant than the gripping structure.

Thus, embodiments of a medical device anchor and method of manufacturethereof are disclosed. The disclosed embodiments are presented forpurposes of illustration and not limitation.

1. A method of manufacturing the medical device anchor, the methodcomprising: forming a gripping structure defining a through hole havinga circumference, wherein axial, circumferential and radial directionsare defined relative to the through hole, the gripping structure forminga continuous, serpentine arrangement having a plurality of compressibleaxial segments arranged in a generally parallel, spaced apart arrayalong the circumference of the through hole, each axial segment havingfirst and second ends; and a plurality of shoulder segments separatedfrom one another in alternating fashion by a plurality of shoulder gapsforming a generally annular array of shoulder segments and shouldergaps, the first ends of the axial segments being alternately bridged orunbridged by the shoulder segments and shoulder gaps, the shouldersegments extending radially outward relative to the through hole furtherthan the axial segments; a plurality of bridging segments separated fromone another in alternating fashion by a plurality of unbridged gapsforming a generally annular array of bridging portions and unbridgedgaps, the second ends of the axial segments being alternately bridged orunbridged by the bridging segments and unbridged gaps such that thegripping structure forms a serpentine arrangement of a continuous naturewith the compressible beams alternately interconnected between shouldersegments and bridging segments; and molding a body portion on thegripping structure to securely capture the shoulder segments in the bodyportion, the body portion being molded of material that is softer andmore compliant than the gripping structure.
 2. The medical device anchorof claim 1 wherein the step of forming a gripping structure furtherincludes: forming a grip-enhancing texture along a radially-inwardlyfacing surface of each axial segment, the grip-enhancing texture beingformed for frictional engagement with a lead or catheter in use of themedical device anchor.
 3. The medical device anchor of claim 2 whereinthe step of forming a grip-enhancing texture along a radially-inwardlyfacing surface of each axial segment further includes: forming threadsor grooves along the radially-inwardly facing surfaces of the axialsegments.
 4. The method of claim 1, further including: covering thegripping structure with a sleeve prior to molding the body portion. 5.The method of claim 1, wherein the shoulder segments form a shoulderwhen compressed.
 6. The method of claim 2, wherein the body portionincludes a midportion having a plurality of bumps on an outer surface.